One traditional method of forming seams in wetsuits formed from closed cell neoprene based materials involves gluing together a butt seam where a rubber-like glue is applied to each of the faces to be butt joined and subsequently butting the faces together and allowing the glue to dry or cure. Although such seams are relatively quick and simple to form, they have been found to have inadequate strength for vigorous active water sport activities such as surfing and wind surfing.
In another method of forming seams, a glued and butted seam of the above type is strengthened by zig-zag stitches across the seam. However, with such a strengthened seam, when the seam is placed under stress during vigorous activity the needle holes become enlarged allowing water to penetrate through the holes to the interior of the suit. In addition the zig-zag stitching is generally unattractive while such a stitching technique is relatively complicated and therefore costly to utilize.
A further advance in the above glued, butted and zig-zag seam involves gluing a flexible tape on opposite sides of the seam, which improves the seam strength and waterproofness, but the addition of the glued tape decreases the flexibility of the seam, whilst also adds a further step to the manufacturing process thus increasing the cost of the procedure.
In one still further proposal, a glued and butted seam, not using zig-zag stitching, has applied to it a thin elastic tape glued manually over the seam or using a hest sensitive tape applied by a hot iron or machine. As there are no stitch holes through the material the seam has good waterproofness. However, seam strength is reduced unless both sides of the joint are taped, but such detracts from the appearance of the wetsuit whilst the cost of production is increased and the flexibility of the seam is also reduced.
In another still further proposal, a glued and butted seam, not utilizing zig-zag stitching, has an elastomeric coating applied over the butt joint on one side and such a seam construction is disclosed in U.S. Pat. No. 3,294,617. However, although the seam is relatively flexible and waterproof, the elastomeric coating, in being on one side only, lacks sufficient strength for the types of activities in question and is still costly to produce, whilst if the coating is applied to both sides the cost is still further increased and the resulting wetsuit is more difficult to don and remove due to the relatively high co-efficient of friction which such coating materials exhibit, and as such the joining technique has found very little commercial application for surfing and wind surfing purposes.
In another still further proposal a glued and butted joint is subsequently blind stitched or cup-seamed on either one or both sides to produce a relatively flexible seam having good waterproofness and seam strength, particularly if sewn on both sides. However, the result is a less attractive seam, whilst production costs are once again high. An advance on this type of seam has utilized a glued down flexible tape, or a heat sensitive tape, on one or both sides of the seam which still further improves the strength and waterproofness of the resulting seam, and although currently used extensively for suits for cold water conditions the production costs are particularly high and flexibility is also reduced.
A still further seam construction which has been proposed, once again involves butting together the edges to be joined and applying an elastic tape along the joint. The tape is stitched into the material and the resulting joint is known as a Mauser joint. Although this technique involves a relatively simple one step process, it is not sufficiently waterproof and thus is not suitable for cold water conditions.